1. Field of the Invention
The present invention relates to a magneto-resistive random access memory and a method of manufacturing the same. More particularly, the present invention relates to a magneto-resistive random access memory having a tunneling junction and a method of manufacturing the same.
2. Description of the Related Art
Magneto-resistive random access memories (RAMS) are formed of metal oxide semiconductor (MOS) transistors and magnetic tunneling junctions which are electrically connected to the MOS transistors to serve as signal storing capacitors. Thus, recorded data can be read via the magnetic tunneling junctions by applying a predetermined voltage to the MOS transistors.
A magneto-resistive RAM has the advantages of speed and non-volatility, making it very suitable for use as a memory device. Also, a magneto-resistive RAM has a cell structure that allows structures of peripheral circuits to be simplified.
Magneto-resistive RAMs generally use a memory core that connects MOS transistors and magnetic tunneling junction devices in series. Here, a data storage device must have a resistance value greater than that of a MOS transistor operating as a simple switch. Thus, magnetic tunneling junctions are currently used as memory devices of magneto-resistive RAMs.
Currently used magnetic tunneling junctions include an oxide aluminum layer (Al2O3) as an oxide barrier. The oxide aluminum layer (Al2O3) is formed by depositing and then oxidizing an aluminum (Al) layer. The oxide barrier serves as a potential barrier in the magnetic tunneling junction.
However, a potential barrier formed by such an oxide layer barrier is not refined, and thus a magnetic resistance ratio (hereinafter referred to as a MR ratio) tends to be reduced by an amount inversely proportional to an applied voltage. The reduction in the MR ratio may cause an operation error when storing and reading data, thereby greatly deteriorating the reliability of such a memory device.